On-roof gutter

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On-roof gutter
Installation of drip edge
Installation of on-roof gutter brackets
Installation of on-roof gutter
Gluing on-roof gutter joint
Installation of on-roof gutter expansion joint
Installation of on-roof gutter stop end

When planning on-roof, care must be taken to ensure that these are installed at the level of the roof covering above the sub-roof/underlay running underneath or above the ventilation level.

The starter flashings are designed and executed to be cut to 500 mm in sections up to 3 m in length, up to a cut of 800 mm in sections up to 1 m in length. The regulations for seam roofing apply to dimensions wider than 800 mm.

The edge plate must be at least 15 cm behind the overlying area of the edge gutter and should have a cut of at least 400 mm.

Below a roof pitch of 25°, roof edge plates must have a rear edge of at least 15 mm.

The PREFA on-roof gutter is generally designed for a minimum slope of 3 mm/m. In certain circumstances however, the PREFA on-roof gutter can also be designed without a slope.

Note

In the case of a reduced slope, increased cleaning or maintenance is to be expected.

It is important to ensure that the roof gutter rear edge is 10 mm higher than the front of the edge gutter. This results in a minimum roof pitch of 20° for PREFA on-roof gutters (see figure below).

Minimum roof pitch PREFA on-roof gutter

Install the eaves starter flashing in accordance with national standards and technical regulations (Fig. 1).
Flatten the seams on the top outwards (Fig. 2).

Note

Flatten the seams that the on-roof gutter overlaps 150 mm minimum. Mind fall

Fit gutter bracket at low and high point in the rafter. Usually gutter brackets should be installed following rafter spacing (Fall approx. 3 mm per metre) (Fig. 1).
Tighten the string in the watercourse and at the front of the gutter bracket. Install gutter brackets with provided fall (Fig. 2).

Insert on-roof gutter and tighten the spring of the bracket. Starting at the lowest point. The overlap of the gutter joint must be installed in the direction of the slope (Fig. 1).
Trim the on-roof gutter at the upper end to the required length (Fig. 2).

Attention

It is important to ensure that the roof gutter rear edge is 10 mm higher than the front of the edge gutter.

Prepare and bend back rear edge (Fig. 3).
Fix rear edge with clips (Fig. 4).

Product	Joints
On-roof gutter	approx. 5

On-roof joint with 1 special adhesive cartridge

Mark overlapping area (approx. 8 cm) at the bottom or top of the edge gutter and roughen the surface (Fig. 1).
Clean the sanded glued surfaces with the PREFA adhesive cleaner. Wait for the cleaner to evaporate for about 5 min. (Fig. 2).
Open the over-twisting on-roof gutter bead with the PREFA gutter bead opener to make it easier to twist later (Fig. 3).
With PREFA special adhesive, apply a bead of adhesive (approx. 8 mm thick) approx. 50 mm before the end of the gutter (Fig. 4).
Twist the on-roof gutter together (overlap ~ 8 cm) (Fig. 5).
Fit a rivet to the gutter bead. Fix the gutter in the centre with an additional rivet (Fig. 6).

On-roof gutter joints can also executed with 20 pcs. of 4 x 9.5 mm PREFA rivets in a cross stitch version and sealed with PREFA silicone.

Prepare the on-roof gutter bead and twist the edge gutters to be connected together - overlap approx. 8 cm (Fig. 1).
Mark the adhesive surface for the on-roof gutter expansion (width approx. 6 cm) and roughen the surface (Fig. 2).
Clean the surface with provided cleaner. Wait for the cleaner to evaporate for about 5 min. (Fig. 3).
Apply 1 bead of PREFA special adhesive (approx. 8 mm thick) (Fig. 4).
Place the expansion joint in the prepared area and fasten it to the gutter bead and in the centre of the support surface (in the direction of the rafters) with a rivet (Fig. 5).

Note

The joint can be made as a glued or riveted version. Riveted joints must also be sealed with PREFA special silicone.

Insert on-roof gutter stop end and mark the overlapping area (Fig. 1)
Roughen the gluing surface of the gutter and stop end and clean with provided cleaner afterwards. Wait for the cleaner to evaporate for about 5 min. (Fig. 2).
Apply 1 bead of PREFA special adhesive (approx. 8 mm thick) (Fig. 3).
Mount on-roof gutter stop end and fasten it to the gutter bead and in the centre of the support surface (in the direction of the rafters) with a rivet (Fig. 4).

On-roof gutter

On-roof gutter

Installation of drip edge

Installation of on-roof gutter brackets

Installation of on-roof gutter

Gluing on-roof gutter joint

Installation of on-roof gutter expansion joint

Installation of on-roof gutter stop end

Note